[test-improver] test: MSTEST0029 — add edge case tests for virtual/override and make-private fixer

[github-actions]

Goal and Rationale

Improve test coverage for PublicMethodShouldBeTestMethodAnalyzer (MSTEST0029) by closing three gaps in the existing test suite:

1. IsVirtual early-return path — the analyzer silently skips public virtual methods in a test class (line 70 of the analyzer). No test previously exercised a virtual method that does not implement an interface.
2. IsOverride early-return path — same gap for override methods (line 71 of the analyzer).
3. "Change to private" code fix — PublicMethodShouldBeTestMethodFixer offers two code fixes: 1 Add [TestMethod] and 2 Change accessibility to private. The second fix (CodeActionIndex = 1) was entirely untested.
4. Misleading existing test — WhenMethodIsPublicAndMarkedAsTestCleanup_NoDiagnostic used [TestInitialize] in its body, making it a duplicate of the TestInitialize test and leaving the [TestCleanup] suppression path untested. Fixed the test body to use [TestCleanup].

Approach

All additions follow the existing test patterns in the file:

• NoDiagnostic tests use VerifyCS.VerifyAnalyzerAsync (consistent with similar virtual/interface tests nearby).
• The code-fix test uses new VerifyCS.Test { CodeActionIndex = 1 }.RunAsync() — the same pattern used in AvoidAssertAreEqualOnCollectionsAnalyzerTests for multi-fix scenarios.

Changes

test/UnitTests/MSTest.Analyzers.UnitTests/PublicMethodShouldBeTestMethodAnalyzerTests.cs

• Fix: change [TestInitialize] → [TestCleanup] in WhenMethodIsPublicAndMarkedAsTestCleanup_NoDiagnostic body
• Add: WhenPublicVirtualMethodInTestClass_NoDiagnostic
• Add: WhenPublicOverrideMethodInTestClass_NoDiagnostic
• Add: WhenMethodIsPublicAndNotMarkedAsTestMethod_ChangeToPrivateFix

Test Status

Build and all 19 PublicMethod* tests pass:

Test run summary: Passed!
  total: 19, failed: 0, succeeded: 19, skipped: 0

Trade-offs

These are pure test additions — no production code changed. Tests are straightforward with minimal maintenance burden.

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Show patch preview (137 of 137 lines)

From 533b74681ca68c7903cc0a19339dcb07c08d7f5b Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Wed, 8 Jul 2026 23:34:02 +0000
Subject: [PATCH] test: add MSTEST0029 edge cases for virtual/override and
 make-private fixer
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Add three new tests for PublicMethodShouldBeTestMethodAnalyzer (MSTEST0029):

1. WhenPublicVirtualMethodInTestClass_NoDiagnostic — exercises the IsVirtual
   early-return path (line 70 in the analyzer). A public virtual method in a
   [TestClass] that does not implement any interface should produce no diagnostic.

2. WhenPublicOverrideMethodInTestClass_NoDiagnostic — exercises the IsOverride
   early-return path (line 71 in the analyzer). A public override of a non-interface
   base-class method in a [TestClass] should produce no diagnostic.

3. WhenMethodIsPublicAndNotMarkedAsTestMethod_ChangeToPrivateFix — exercises
   CodeActionIndex=1, the "Change accessibility to private" code fix offered by
   PublicMethodShouldBeTestMethodFixer. This fix was previously completely untested.

Also fix WhenMethodIsPublicAndMarkedAsTestCleanup_NoDiagnostic: the test body was
using [TestInitialize] instead of [TestCleanup], making it a duplicate of the
WhenMethodIsPublicAndMarkedAsTestInitialize_NoDiagnostic test and leaving the
[TestCleanup] attribute path untested.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 ...icMethodShouldBeTestMethodAnalyzerTests.cs | 84 ++++++++++++++++++-
 1 file changed, 83 insertions(+), 1 deletion(-)

diff --git a/test/UnitTests/MSTest.Analyzers.UnitTests/PublicMethodShouldBeTestMethodAnalyzerTests.cs b/test/UnitTests/MSTest.Analyzers.UnitTests/PublicMethodShouldBeTestMethodAnalyzerTests.cs
index 88c228e..14604b3 100644
--- a/test/UnitTests/MSTest.Analyzers.UnitTests/PublicMethodShouldBeTestMethodAnalyzerTests.cs
+++ b/test/UnitTests/MSTest.Analyzers.UnitTests/P
... (truncated)